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Anchor Chart - Multiplying Fractions
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Roots of Reason
rootsofreason.org
× means "of"
Anchor Chart · Grade 5 · 5.NF.B.4
Multiplying Fractions
1
4
×
2
3
= one fourth OF two thirds
1
Start With What You Have
2/3 shaded
Draw
two thirds
with up-and-down cuts.
2
Take a Fourth of It
cut into 4 rows, keep 1
Side-to-side cuts make
twelfths
. The dark cells are 1/4 of the 2/3.
3
The Rule the Picture Proves
1
4
×
2
3
=
1 × 2
4 × 3
=
2
12
=
1
6
multiply the numerators, multiply the denominators
The numerators count the kept cells; the denominators count all the cells. That is why the rule works.
4
Does It Make Sense?
· A fourth
of
something is
smaller
than the whole thing, so the answer should be smaller.
1
6
<
2
3
✓
· Multiplying a number by a fraction less than 1 gives an answer smaller than that number.
· A whole number multiplies the numerator: 3 ×
2
5
=
6
5
.
"of" shrinks; the picture shows why.
